/**
 * Licensed to the Apache Software Foundation (ASF) under one or more contributor license
 * agreements.  See the NOTICE file distributed with this work for additional information regarding
 * copyright ownership.  The ASF licenses this file to you under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with the License.  You may obtain
 * a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed under the License
 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
 * or implied. See the License for the specific language governing permissions and limitations under
 * the License.
 */
package org.apache.zookeeper.graph.servlets;

import java.io.IOException;
import java.io.BufferedOutputStream;
import java.io.FileOutputStream;
import java.io.DataOutputStream;
import java.io.PrintStream;

import java.util.HashSet;
import java.util.LinkedHashMap;

import org.apache.zookeeper.graph.*;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import org.json.simple.JSONArray;
import org.json.simple.JSONObject;
import org.json.simple.JSONValue;


public class Throughput extends JsonServlet {
    private static final int MS_PER_SEC = 1000;
    private static final int MS_PER_MIN = MS_PER_SEC * 60;
    private static final int MS_PER_HOUR = MS_PER_MIN * 60;

    private LogSource source = null;

    public Throughput(LogSource src) throws Exception {
        this.source = src;
    }

    public String handleRequest(JsonRequest request) throws Exception {
        long starttime = 0;
        long endtime = 0;
        long period = 0;
        long scale = 0;

        starttime = request.getNumber("start", 0);
        endtime = request.getNumber("end", 0);
        period = request.getNumber("period", 0);


        if (starttime == 0) {
            starttime = source.getStartTime();
        }
        if (endtime == 0) {
            if (period > 0) {
                endtime = starttime + period;
            } else {
                endtime = source.getEndTime();
            }
        }

        String scalestr = request.getString("scale", "minutes");
        if (scalestr.equals("seconds")) {
            scale = MS_PER_SEC;
        } else if (scalestr.equals("hours")) {
            scale = MS_PER_HOUR;
        } else {
            scale = MS_PER_MIN;
        }

        LogIterator iter = source.iterator(starttime, endtime);

        long current = 0;
        long currentms = 0;
        HashSet<Long> zxids_ms = new HashSet<Long>();
        long zxidcount = 0;

        JSONArray events = new JSONArray();
        while (iter.hasNext()) {
            LogEntry e = iter.next();
            if (e.getType() != LogEntry.Type.TXN) {
                continue;
            }

            TransactionEntry cxn = (TransactionEntry) e;

            long ms = cxn.getTimestamp();
            long inscale = ms / scale;

            if (currentms != ms && currentms != 0) {
                zxidcount += zxids_ms.size();
                zxids_ms.clear();
            }

            if (inscale != current && current != 0) {
                JSONObject o = new JSONObject();
                o.put("time", current * scale);
                o.put("count", zxidcount);
                events.add(o);
                zxidcount = 0;
            }
            current = inscale;
            currentms = ms;

            zxids_ms.add(cxn.getZxid());
        }
        JSONObject o = new JSONObject();
        o.put("time", current * scale);
        o.put("count", zxidcount);
        events.add(o);

        iter.close();

        return JSONValue.toJSONString(events);
    }

};
